1. Field of the Invention
This invention relates to an installation for the continuous manufacture of differing mineral fiber products, wherein a predetermined number of control elements are provided for adjusting specific parameters of the products.
2. Description of the Prior Art
Such an installation for the manufacture of mineral fiber products, commonly referred to as a production line, includes, from the fiber forming apparatus to the packing station, various apparata which act on the mineral fiber product for the purpose of adding binder, compressing the product, hardening it, trimming the width, cutting the length, applying a facing if required, rolling up the product, stacking it and wrapping it. For an example of such a production line and an illustration thereof, reference may be made to the specification of DE-OS No. 3,100,003, while the specifications of DE-OS No. 3,036,816 and DE-OS No. 3,325,341 explain the problems encountered in the application of a facing to such mineral fiber products, and the specification DE-OS No. 3,314,289 deals with the problems relating to the control of a winding station at the end of the production line.
Typically, most of the apparata act on the product in a manner which is specific to the particular product and must therefore be regulated afresh each time the line changes over from one product to another. Such regulation is necessary each time a completely new product is to be manufactured, for example a width of mineral fiber sheet or the like which has not previously been produced, and it is also necessary in cases where products which differ among themselves, although of conventional type, are required to be manufactured alternately. Although the change over to products which have not yet hitherto been manufactured generally occurs only a few times per month, the changeover to the manufacture of different products to meet customers' orders generally occurs at least several times per day and frequently several times per hour, for the successive manufacture of small batches of specially required products.
For this purpose, appropriately adjusted control parameters must be applied to the treatment apparatus of the production line. One then encounters the particular difficulty that the adjusted parameters do not always result in exactly the properties of products envisaged and moreover, different properties may be obtained from one case to the other. If, for example, the intake nip between the press rollers is adjusted to a value of, say, 8 cm, the continuous sheet of mineral fibers will certainly be compressed to a thickness of 8 cm in this position but will subsequently expand elastically to a thickness of, say, 12 cm. This elastic recovery will, however, not invariably expand this same sheet of mineral to precisely the same height but will cause it to assume differing heights according to the consistency of the fibers, the binder content, its degree of hardening, etc. These heights differing from one case to another are liable to influence subsequent treatment operations, for example the winding operation as such, the length of sheet required to wrap around the roll of material, it being understood that other magnitudes which also vary according to circumstances may also intervene, as for example the binder content.
All this has the consequence that an accumulation of unfavorable parameters may result in the production of rejects even when all the parameters over the whole apparatus have been precisely regulated according to the product to be manufactured. In the most unfavorable case, a given adjustment of parameters, which may previously have resulted in a satisfactory product, may during a subsequent passage or a reversion to the same product produce a result which is no longer acceptable because in the meantime other circumstances have intervened to result in an unfavorable accumulation of deviations in the properties of the products.
Furthermore, during the interval of time required for adjusting the parameters of the apparatus, the line will inevitably produce rejects, and this may give rise to the accumulation of a considerable quantity of scrap in cases where conversions are frequent. These rejected quantities are not only lost as marketable commodities, but also entail considerable costs for their removal. The quantity of rejected products will obviously be higher where the persons in charge of the installation are less qualified. Where multiple work shifts exist over a 24 hour period, variations in the qualifications of the staff for each shift are inevitable.